Lubricating oil containing branched chain alkyl amine derivatives of dicarboxylic acids



LUBRICATING OIL CONTAINING BRANCHED CHAIN ALKYL AMINE DERIVATIVES OF DI- CARBOXYLIC ACIDS Kenneth L. Godfrey, St. Albans, and Donald D. Staker,

Nitro, W. Va., assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware '4 Claims. (Cl. 255-515 The present invention relates to new compositions of matter and also to mineral oil compositions containing the new products. The compositions comprising the present invention are formed by the reaction, preferably at between temperatures of l20-l60 C., of an alpha-beta dicarboxylic acid containing fewer than 6 carbon atoms or anhydride thereof, with a branched chain primary amine containing at least 10, and preferably, 12 to 15 carbon atoms. However, such amines containing from 18 to 24 carbon atoms have been successfully employed. The desired products, found most effective for use as rust inhibitors of steam turbine oils, are those formed by reacting from 0.5 to 2.0 moles of acid with 1 mole of amine. Moreover, esterification or partial esterification of the carboxyl groups present by means of a long chain alcohol, also results in acceptable products for the use mentioned. The invention will be readily apparent from the discussion and examples that follow.

As suitable and preferred acids found effective as reactants with the disclosed amines, the following group is disclosed:

Malic acid OH HOOO-(iH-CHLCOOH Succinic acid HOOC.CH .CH .COOH Fumaric acid HOOC.CH=CH.COOH Maleic acid HOOC.CH=CH.COOH (cis) Tartaric acid OH OH HOOC.CHCH.C O OH Itaconic acid fill nooocmcooorr Aspartic acid l HOOC.CHr-C.COOH

The branched chain amines employed in the present invention preferably are tartiary-alkyl primary amines, as for example Primene 8l-R which is a tertiary-alkyl amine containing 12 to 15 carbon atoms and Primeme JMR which is a tertiary-alkyl amine containing 18 to 24 carbon atoms. The use of such amines is essential in order to produce a final product of required oil solubility. Suitable alcohols for esterification of the acid are long chain alcohols such as Ocenol, a mixture of C C unsaturated alcohols, tridecanol, oleyl and octyl alcohols.

The preferred reaction products are readily produced as is evidenced by the following typical example for the class claimed hereinafter. Equal moles of malic acid (134.0 parts) and of Primeme 81-R (201 parts of a Patented Mar. 28, 1961 C -C tert-alkyl primary amine) were weighed into a 500 cc. three-necked fiask, fitted with a thermometer, stirrer and Dean-Stark water trap and condenser. The temperature of the mixture was then raised to 135 C. and a sufiicient quantity of benzene added to maintain refluxing at temperature between 135l40 C. This same refluxing temperature was maintained for a period of 16 hours during which time a total of 35.5 grams of water were collected. Thereupon benzene was removed from the reaction mixture by vacuum distillation at about 135" C. and under 20 mm. of mercury pressure. A very viscous amber liquid was obtained with a neutralization numbertmilligrams of KOl-I eqivalent to' l gm.

of product) of 155.

Although the above specific example shows equi-molar ratios of acid and amine charged, other ratios between the units of 0.5 to 2.0 moles of acid or anhydride per mole of amine have been employed. Likewise, the temperature of reaction has been varied between and 160 C. Obviously at the lower temperatures shown, a longer reacting period is required to complete the reaction as would be shown by the weight of water evolved. If a product is desired in which partial or complete esterification is effected, the alcohol is added in equimolar ratios with the rest of the charge and the described process followed.

Data set forth in the table below illustrate the results of a number of preparations of various products of the preferred class by the procedure described above.

Table 1 Reaction Reaction Solubility Molar Ratio of Acid, Amine Temp, Time, N.N. in Petroand Alcohol 0. hours leum Ether (5% Gone.)

1 Mnlic, l Primeme 81R 135-14 16.0 155 soluble. 1 Malic, 1 Primeme 8l-R, 1 145 7.5 59 clear.

Ocenol. 1 Malic, l Primeme 81-13, 1 140 10.5 61

Tridccanol. 1 Mnlcie, 1 Primeme 81-R 140-158 24.0 1 Fumaric, 1 Primenc 81R 145-155 2.4 114 soluble. 1 Sun-citric, 1 Primcne til-R... 145-150 24.0 128 cloudy. 1 Fumaric, 2 Primenc 81-11.. 67 soluble. 1 Maleic Anhydride, 1 Pri- 145160 49.0 67 clear.

mane 81 -11. 1 Mnlic. 1 Primeme JMR-.... 140 20. 5 96 1 Tartaric, 1 Primcne JMR. 130-135 21.0 83 soluble. 1 MlliiU. 0.5 Primeme .TMR--- 13 5 171 D0. 1 Malic, 2 Primeue JMR. 137-143 29. 5 105 clear.

The effectiveness of various products within the scope of the present invention and prepared in the manner hereinbefore described, as rust inhibitors in mineral lubrieating oils, for example an oil suitable for use in steam turbines, was determined in accordance with A.S.T.M. Test D 665-521 for determining the rust preventing characteristics of steam turbine oils in the presence of water. In accordance with this test, both synthetic sea water and distilled Water are used. The synthetic sea water was prepared as described in the above identified test method. In the test a cylindrical, polished steel specimen is suspended and soaked in 300 cc. of the oil under test at 140 F. for 30 minutes. Thereafter, 30 cc. of synthetic sea water (or 30 cc. of distilled water) are added and the mixture is stirred at 1000 r.p.m. After 24 hours the steel specimen is removed and examined for evidence of rust. The oil containing the inhibitorunder test passes the test when there is no evidence of rust on that part of the specimen which hangs below the oil level.

In the test results set forth in Table 2 following, the oils employed were base stocks in commercial use for the formulation of light and heavy steam turbine finished lubricants. The different base oils are designated by the letters A, B, C and D. The base stocks were treated with the indicated percentage by weight of the various products of the preferred type as indicated, which products possess the neutralization number as shown.v

Trible Z This application is a division of US. patent application Serial Number 503,009, filed April 21,1955, now abandoned.

Molar Ratio of Acid/Amine Cone.

N .N Oil percent Rust Test Dist. Sea

1 Maleic, 1 Primene 81-R Do 1 1 Fumaric, 1 Primene 81-R 114 Do 1 40 1 Maleic anhydride, 1 Prirrene 81-R 193 06 1 Succinic, 1 Primene 81R.- 128 10 1 Fumaric, 2 Primene 81-R 67 10 1 Malic, 1 Oleyl alcohol, 1 Primene 81R 69 12 Do. light staln borderline.

no rust pass.

o Do. do Do.

1 50% blend with kerosene.

To determine Whether or not the addition of the reaction products of this invention to lubricating oils cause the formation of undesirable emulsions, emulsion tests were also carried out on the oil-reaction product mixtures in accordance with the emulsion test for lubricating oils according to Method 320.1.5, Federal Specification VV-L-791d, Federal Stock Catalog Sec. IV, Part 5. According to'this test, 40 cc. of the compounded oil and 40 cc. of water are placed in a 100 cc. of graduated cylinder and stirred by suitable means at 1500 r.p.m. for 5 minutes at the prescribed temperature. Separation of the resulting emulsion is observed while the cylinder and contents are kept at the required temperature. The time in minutes for the separation of an emulsion layer of 3 cc. thickness and the time for complete breaking of the emulsion is shown in Table 3. Tests were carried out in distilled and in 1% NaCl solution as indicated, employing the reaction products shown with the turbine base stocks used in the rust tests previously described. In order to meet Navy Specification MIL-L-17331 (Ships) there must not be over 3 cc. of emulsion after minutes The results of the several tests set forth clearly show that the new reaction products of the class described are oil soluble, are effective in protecting a metal against rusting in oil-water contact and do not form continuous oil-water emulsions.

It is intended to cover all changes and modifications of the examples of the invention herein chosen for purposes of disclosure which do not constitute departures from the spirit and scope of the invention.

What is claimed is:

1. A mineral lubricating oil containing from .021% by weight of an oil soluble acidic reaction product obtained by reacting a member selected from the group consisting of malic, succinic, fumaric, maleic, tartaric, itaconic and aspartic acids and anhydrides thereof with primary branched chain alkyl amine containing 1024 carbon atoms, the reaction being conducted Within the range of 160 C. with from 0.5-2.0 moles of the acidic reagent per mole of amine, and accompanied by formation of by-product water.

2. A mineral lubricating oil containing from .021% by weight of an oil soluble acidic reaction product obtained by reacting an alpha, beta-dicarboxylic acid of the structure HOOCC H,,COOH where n is an integer at least 2 but less than 5 with a primary branched chain alkyl amine containing 10-24 carbon atoms, the reaction being conducted within the range of 120-160 C. with from 0.5 to 2.0 moles of the acidic reagent per mole of amine, and accompanied by formation of by-product water;

3. A mineral lubricating oil containing from .021% by weight of an oil soluble acidic reaction product obtained by reacting substantially 134 parts by weight of malic acid with substantially 201 parts by weight of a mixture of tertiary alkyl primary amines containing 12-15 carbon atoms in the alkyl group at a temperature of 135-140 C., the reaction being accompanied by formation of by-product Water.

4. A mineral lubricating oil containing from .021% by weight of an oil soluble acidic reaction product obtained by reacting equal molecular proportions of maleic acid and a mixture of tertiary alkyl primary amines containing 12-15 carbon atoms in the alkyl group at a temperature of -150 C., the reaction being accompanied by formation of by-product water.

References Cited in the file of this patent UNITED STATES PATENTS 2,191,738 Balle Feb. 27, 1940 2,490,744 Trigg et al. Dec. 6, 1949 2,594,286 Bryant et al. Apr. 29, 1952 2,604,451 Rocchini July 22, 1952 2,699,427 Smith et al. Jan. 11, 1955 2,718,503 Rocchini Sept. 20, 1955 2,739,871 Senkus Mar. 27, 1956 2,742,432 Messina Apr. 17, 1956 2,742,498 Smith et al. Apr. 17, 1956 2,758,086 Stuart et al Aug. 7, 1956 2,783,206 Messina Feb. 26, 1957 

1. A MINERAL LUBRICATING OIL CONTAINING FROM .02-1% BY WEIGHT OF AN OIL SOLUBLE ACIDIC REACTION PRODUCT OBTAINED BY REACTING A MEMBER SELECTED FROM THE GROUP CONSISTING OF MALIC, SUCCINIC, FUMARIC, MALEIC, TARTARIC, ITACONIC AND ASPARTIC ACIDS AND ANHYDRIDES THEREOF WITH PRIMARY BRANCHED CHAIN ALKYL AMINE CONTAINING 10-24 CARBON ATOMS, THE REACTION BEING CONDUCTED WITHIN THE RANGE OF 120-160*C. WITH FROM 0.5-2.0 MOLES OF THE ACIDIC REAGENT PER MOLE OF AMINE, AND ACCOMPANIED BY FORMATION OF BY-PRODUCT WATER. 